Part 4

That neither Lilienthal nor any other experimenter had ever tried any more adequate method to insure lateral balance struck Orville as surprising. Why, he asked himself, wouldn’t it be possible for the operator to vary the inclination of sections of the wings at the tips and thus obtain force for restoring balance from the difference in the lifts of the two opposite wing tips? That seems today an obvious enough idea, but no one had ever done anything about it before. Orville had hit on a fundamental principle. (Indeed, this principle later became the basic claim of the original Wright patent, and the claim was sustained, as covering the idea of the aileron control, in all countries where the Wright patents were adjudicated.)

Orville made a rough sketch of a wing, showing a stationary section at the center, consisting of approximately one-third of the wing, measured from tip to tip, with two adjustable sections, one at either side. These sections were carried on shafts interconnected by cogs mounted on the center section and extending toward the wing tips. The movement of a lever attached to one of the shafts would cause one wing section to rotate in one direction while the other wing would turn in the opposite direction. Thus a greater lift could be obtained on whichever side it was needed.

The Wrights soon saw, however, that for two reasons this particular design did not provide a good structure for a gliding machine. First, with two-thirds of the entire weight of the machine and operator carried by the two shafts, the structure would be weak; and, second, with the ends of the wings free to turn about the shafts, there would not be enough rigidity for a machine that would have to be toted about.

Then one night, some five or six weeks later, Wilbur came home from the bicycle shop, to tell Orville enthusiastically of an idea he had hit upon. A customer had dropped in to buy an inner tube for a tire. Wilbur had taken the tube from the pasteboard box it came in and was toying with the box while talking to the customer. As he twisted the box he observed that though the vertical sides were rigid endwise, the top and bottom sides could be twisted to have different angles at the opposite ends. Why, he thought, couldn’t the wings of a gliding machine be warped from one end to the other in this same way? Thus the wings could be put at a greater angle at one side than at the other, without structural weakness. That plan seemed so satisfactory that the Wrights did not look for or consider any other method.

A few weeks later, in August, 1899, the brothers built a biplane kite, and Wilbur, with a group of small boys as spectators, flew it on a common at the edge of town. This kite had wing surfaces five feet from tip to tip by thirteen inches wide. The warping of these surfaces could be accomplished by the use of four cords reaching from the kite to the ground. Two of the cords were attached to the forward corners of the right wing tips, one to the upper and one to the lower; the other ends of the cords, at the ground, were tied to opposite ends of a short stick to be held in the operator’s hand. The cords tied to the left wing were arranged in the same way. With a stick in each hand, the operator could move the wings as he desired. The upper wing could be moved farther forward or farther backward than the lower wing, according to the direction in which the two sticks were simultaneously inclined, by movement of the wrists. By inclining the two sticks in opposite directions it was possible to draw one upper wing tip farther forward than the lower at that end, while at the other end of the kite the lower wing tip would be the one farther forward. This moving of the wing tips in opposite directions caused a twisting or warping of the wings. Then the wing at one end would be presented to the wind at a different angle from that at the other end. If one end of the kite started to sink, sidewise balance could be restored by exposing the wing at that end at a greater angle, thus getting more lift.

Balance from front to rear was to be maintained by inclining the two sticks in the operator’s hands in the same direction--to move the upper wing either forward or backward over the lower wing, to change the center of lift.

But in addition to this moving of the wings forward and backward, the Wrights added an “elevator” at the rear. It was held by a pair of wooden rods attached at right angles to the uprights that connected the wings. When the upper wing was pulled forward, to turn the kite upward in front, the elevator met the air at its top side and was pressed downward, which helped to turn the wings upward--as the rear elevator does on planes today.

Though their interest did not lag, the Wrights did nothing more for some time about kite experiments, except to seek information in regard to wind velocity in different parts of the country. They wrote to the Weather Bureau at Washington, in December, 1899, and Willis Moore, chief of that Bureau, sent them a number of government bulletins that included statistics on wind velocities at various places. They looked these over, but at that time made no further investigation of any of the places mentioned.

In May, 1900, Wilbur Wright wrote a letter to Octave Chanute, living in Chicago, who had written _Progress in Flying Machines_. Though Chanute was better known in engineering circles by his work for certain western railroads, as well as for having built the Kansas City bridge and the Chicago stockyards, his book, a reprint of his articles published from 1891 to 1893, had made him probably the best authority on the history of aeronautics. Thinking Chanute would be interested, Wilbur told him in his letter of a plan he had for experimenting with a man-carrying kite by means of which, Wilbur thought, one would be able to get hours of practice in operating a machine in the air. He proposed the use of a high tower from the top of which a cable would lead to the man-carrying kite. He described to Chanute, in his letter, the system of control to be used in the kite--the warping of wings for lateral control, and the shifting of the upper surface backward and forward for longitudinal control--the same system used in the five-foot kite tested the previous August. Then he asked Chanute if he had any information as to locations where winds suitable for carrying on such experiments might be found. (This letter from Wilbur marked the beginning of an acquaintance and correspondence with Chanute that lasted for a number of years.) Chanute suggested San Diego, California, and St. James City (Pine Island), Florida, to be considered because of the steady sea breezes. But, on the other hand, he pointed out that, since those places were deficient in sand hills, perhaps even better locations could be found on the Atlantic coast of South Carolina or Georgia.

When the rush of the spring trade in bicycles began to subside, giving them more time for other interests, the Wrights again took up with enthusiasm the study of equilibrium. Each day they proposed and discussed new devices. Orville thought the shifting of the upper surface backward and forward over the lower one, for longitudinal equilibrium, though successful in their kite, would not be practical for a man-carrying glider, which would start and land on the ground. He suggested that the wing surfaces be fixed one above the other, and that an elevator be placed some distance in front of the wings, instead of at the rear. In this position there would be less danger of the elevator touching the ground in starting; and if from any cause the elevator were disabled it would be discovered before the machine got into the air. Wilbur then proposed that, since curved surfaces were more efficient than flat planes, the front rudder, or elevator, should be made flexible. Then it could be bent to present a concave surface on whichever side a pressure was desired, but would be flat when moving edgewise through the air.

The Wrights did not at first think an elevator in front would provide inherent stability--that is, it would not give the machine the desired tendency to restore its own balance just from the arrangement of its fixed parts. But Wilbur shortly afterward developed a theory that led him to believe the machine would have that quality.

Having read that the center of pressure moves toward the front edge of the wings whenever the wings are turned more nearly horizontal in flight, he thought inherent longitudinal stability could be obtained if the front elevator were set at a negative angle--that is, with its front edge lower than its rear edge. With such an arrangement of wings and elevator, every time the wings became more nearly horizontal in flight and met the air at a smaller angle on their under sides, the elevator would meet the air at a greater angle on its upper side. So, he reasoned, whenever, by becoming more nearly horizontal, the wings caused the center of pressure to move forward, tending to turn the machine upward in front, the front elevator would receive a greater downward pressure on its upper side and so counteract the disturbing pressure on the wings.

Actual tests later proved that the negative angle of the front elevator did not provide the inherent stability expected. The explanation was that the center of pressure on cambered wings traveled in the opposite direction from that which Wilbur’s reading had led him to expect. The Wrights later were to discover that Wilbur’s reasoning was correct; but because the travel of the center of pressure was rearward instead of forward the elevator had to be set at a positive instead of at a negative angle.

The Wrights’ elevator possessed three features not found in the gliders of any of the earlier experimenters. It was in front of the wings, where it was less liable to damage by striking the ground in take-off and landing; it was operable, instead of fixed as in other machines; and it flexed to present a convex surface to the air, instead of a flat surface. At this early stage of their work the Wrights considered this front elevator their most important invention, because, from their reading, they thought it was solving a problem more difficult than that of lateral control.

Though the Wrights’ reasons for placing the elevator in front of the wings were at first those just mentioned, they afterward found that this arrangement had much greater importance for two reasons not at first discovered. One of these was that it eliminated all danger of a nose dive when the plane got into what is known as a “stall”--when the speed became too slow. The other reason was that the elevator in front, set at a positive angle with the pressure on its under side, not only produced inherent stability, but also carried part of the load, and so relieved the wings to that extent. (An elevator in the rear, set at a negative angle to provide inherent stability, carries a pressure on its upper side, which adds just that much to the load the wings must carry.)

Around the first of August, 1900, the brothers decided to build a man-carrying glider on which to try out their inventions. To get practice in operating it they would first fly it as a kite. For such kite flying, flat open country would be needed; and for the gliding, sand hills free from trees or shrubs. Once again they examined the reports they had received from the Weather Bureau at Washington. Several of the places where winds might be suitable were in the Far West, but one in the East, much nearer to Dayton, was a place with an odd name, Kitty Hawk, North Carolina. They decided to write at once to Kitty Hawk for further information.

Wilbur Wright addressed a letter to the chief of the Kitty Hawk weather bureau station, asking for various details about the locality, explaining that he might wish to go there shortly to conduct experiments with a man-carrying kite. He inquired, too, if it would be possible for him and his brother to obtain board and lodging in the vicinity until they could get themselves established in a camp.

Joseph J. Dosher, in charge of the Kitty Hawk station, who received the letter, replied briefly, on August 16, giving the direction of the prevailing winds; and he described the nature of the land for many miles.

After writing his reply, Dosher handed Wilbur Wright’s letter to a neighbor, William J. Tate, with the request that he also make a reply. “Bill” Tate (later known as Captain Tate) was probably the best-educated man in that locality. He lived about a mile inland from the weather station, in the hamlet or settlement of Kitty Hawk, where he had formerly been the postmaster. For all practical purposes he still was the postmaster, though the office was in his wife’s name. Endowed with a gift for expressing himself readily in either speech or writing, Tate did a creditable job when he wrote to Wilbur Wright on August 18. Not only did he tell about the suitability of the Kitty Hawk region, because of the prevailing high winds, for the kind of experiments Wilbur had mentioned, but he went into details about the treeless sand hills and the general terrain. And he said arrangements could undoubtedly be made for the Wrights to obtain board for as long as desired.

The letters from Dosher and Tate--particularly the one from Tate--convinced the Wrights that Kitty Hawk was the place for their experiments. Almost immediately they decided they would go to Kitty Hawk as soon as they could build their glider.

The work at Dayton, getting parts and material ready for the glider, required only a few weeks. Only the cutting and sewing of the cloth covering for the wings, the bending of the ash ribs into shape, and making the metal connections, took much time. The cost of the whole machine in actual money outlay was trifling, probably not more than $15.

It was arranged that Orville should stay in Dayton, to look after the bicycle shop until Wilbur got settled at Kitty Hawk, and then join him there.

Wilbur set out on a September day, taking with him parts of the glider and all material needed to assemble it except some spruce lumber he expected to obtain nearer his destination.

The journey proved to be more of an undertaking than Wilbur expected.

V

GLIDING AT KITTY HAWK

One must look at a map of North Carolina to get an idea of the isolation of the long strip of sandy beach that separates the Atlantic Ocean from Albemarle, Pamlico, and Roanoke Sounds. At the time the Wrights went there, no bridges connected this beach with any part of the North Carolina mainland or even with near-by Roanoke Island, seat of Sir Walter Raleigh’s “Lost Colony.” At one point on the beach was the Kitty Hawk life-saving station, and alongside of it a government weather bureau. About a mile back from the ocean was the hamlet of Kitty Hawk which, though it had a post office, was little more than a settlement, with only about a score of dwelling houses, most of them as widely scattered as in an ordinary farming community. Four miles south was the Kill Devil life-saving station.

It was not surprising that when Wilbur Wright, on September 9, 1900, reached Elizabeth City, North Carolina, the nearest railroad point to his destination, the first persons he chanced to ask about Kitty Hawk had never heard of the place. Then he learned that a boat made weekly trips to Roanoke Island; but it had gone the day before. Not liking delay, he went to the water front to inquire if another boat might be available. There he met one Israel Perry, formerly a resident of Kitty Hawk, who lived the year round on his little flat-bottomed schooner. As no other boatman showed any interest in making the trip, Wilbur booked passage with “Captain” Perry, despite the boat’s dirty, forbidding appearance. After loading parts of the glider and other goods that had been shipped from Dayton, he set out with Perry on the morning of September 10 for the forty-mile voyage to Kitty Hawk. Wilbur noticed that the small boat they used to go from the wharf out to where the schooner was anchored was leaking badly and he asked if it was safe.

“Oh,” Perry assured him, “it’s safer than the _big_ boat.” That didn’t inspire too much confidence in what was in store, and Wilbur soon learned that any misgivings he felt were amply justified. Toward the middle of the afternoon they met a strong head wind that forced them to seek a smooth water haven in North River where they anchored to await better weather. By that time Wilbur had worked up a good appetite; but he discovered that neither the food nor the kitchen met even minimum standards of cleanliness and he made excuses, as politely as he could, for not eating. All he had with him against hunger was a small jar of jelly his sister Katharine had slipped into his suitcase.

The weather was not favorable for continuing the voyage until the afternoon of the second day, and the boat reached a wharf, where there was a small store, on Kitty Hawk bay, at about nine o’clock that night. Not knowing where else to go, Wilbur stayed aboard until the next morning. A small boy named Baum agreed to guide him to the home of William J. Tate, about a quarter of a mile away. By the time Wilbur arrived there, on that morning of September 12, it was just forty-eight hours since he had tasted food other than his little supply of jelly.

After introducing himself, and in response to “Bill” Tate’s inquiries about how he enjoyed his trip, Wilbur spoke of his back being sore from lying on deck and of how his arm ached from holding on when the boat rolled. Then it came out that he had been unable to bring himself to eat the food provided on the Perry schooner.

“You mean to tell me,” asked “Bill” Tate, greatly concerned, “that you’ve eaten no victuals for two days?”

Here was a situation that called for quick action in a hospitable home. It was after the Tates’ breakfast hour, but Mrs. Tate soon had a fire in the kitchen stove and prepared a great platter of ham and eggs that the guest seemed to relish.

Then Wilbur inquired if it would be possible for him to obtain board and lodging there for the week or more until his brother “Orv” arrived.

Tate went into an adjoining room to ask his wife. As the door was ajar, Wilbur could hear what was said. Mrs. Tate was a bit alarmed. Here was a man able to devote time and money for weeks at a time to sport. Doubtless he must be a person of great wealth, accustomed to every luxury. Would he be satisfied with the best they could offer?

Wilbur stepped to the door, explaining that he could not help overhearing their conversation, and said it must be understood that if he were accepted as a paying guest he would not expect any extra frills, but would greatly appreciate the courtesy.

“This fellow’s a real gentleman,” thought Tate, and by way of settling the question, without waiting to hear any more from his wife, he said to Wilbur:

“You must be tired. Why don’t you come into our spare bedroom and take a nap?”

By the next day Wilbur was at work. The cloth covering for the glider--white French sateen of extra good quality--had already been shaped and sewed at Dayton, except at the ends, to permit fitting it over the framework. But now he had to make changes in the covering, because the glider was going to be smaller than originally planned. The longest timbers, for the wing spars, that he had been able to find in either Norfolk or Elizabeth City were only sixteen feet long instead of the eighteen-foot length he desired. Thus it was necessary to cut out strips from the middle of the lengths of cloth for both upper and lower wings. For resewing the cloth where necessary, Wilbur borrowed Mrs. Tate’s machine. But all the rest of the work of assembling the glider was done at a tent Wilbur set up, about half a mile from the Tate home, at a spot where there were a few trees and a view of the bay. He dragged the crates, containing various parts and tools, to the tent and hoped to have everything in readiness when Orville arrived. But the heat was intense, the job of carrying water to the camp used up much energy, and when Orville got there, on September 28, Wilbur told him regretfully that much work on the glider was still to be done.

Orville’s trip had been uneventful. Indeed, though he came on a better boat than Israel Perry’s, he had struck such a calm sea that his voyage from Elizabeth City took two days, the same as Wilbur’s. For the first five days after Orville’s arrival, both brothers stayed at the Tate home. Then they established themselves in camp. One end of their tent, twelve by twenty-two feet, was tied to a tree for anchorage. The tree was headquarters for a mocking bird that sometimes joined in the harmony when Orville twanged at a mandolin he had brought from home.

Not many visitors came to the camp from near-by Kitty Hawk. One reason for this was that the camp was considered dangerous after news got about that the Wrights used a gasoline stove. “Bill” Tate was favorably impressed, though, with an acetylene lamp, intended for a bicycle, that the Wrights used for lighting. He said he had a notion to install such a system of gas lighting in his house.

It was necessary to carry water about one thousand feet over the sand. Orville volunteered to do the cooking--and he continued to do so during all their experiments at Kitty Hawk. But he always felt that he had the better of the bargain, for the dish-washing job was Wilbur’s. As it was impossible to obtain fresh bread, Orville learned to make biscuits, and without use of milk. They were good biscuits, too--better, his father afterward insisted, than anyone else could make. To simplify operations, Orville always mixed at one time enough flour and other dry ingredients to last for several days, as biscuits had to be baked three times daily.

Working together, the brothers soon had the glider assembled. When completed it weighed about fifty-two pounds. Though the main spars were only sixteen feet long, the “bows” at the ends of each wing surface brought the total span to nearly seventeen and one-half feet. The total lifting area was 165 square feet instead of 200 as intended. A space eighteen inches wide at the center of the lower surface where the operator would lie, with feet over the rear spar, was left free of covering. The apparatus had no rear vanes or tail of any kind; but it had two important features never used by previous experimenters. One was the front rudder, or “elevator,” the rear edge of which was about thirty inches from the nearest edge of the wings; the other was the wing warping. By an ingenious arrangement of the trussing, the wings could be twisted into a helicoidal warp from one end to the other, thus exposing one wing to the air at a greater angle than the other. This was to be used for bringing the machine back to the level after it was tipped up sidewise by a gust of wind.

The Wrights’ first surprise at Kitty Hawk was that the winds there were not what they had counted on. United States Weather Bureau reports had led them to think they would have winds of about fifteen miles an hour almost every day. But now it dawned on them that fifteen miles an hour was simply the daily average for a month. Sometimes the wind was sixty miles an hour, and the next day it would be entirely calm. It now began to look as if they might frequently have to wait a few days for suitable conditions, which meant that their experiments would require more time than they had expected.